This is a self-contained, tutorial introduction to two-dimensional crystal science and technology. Including concise descriptions of experimental methods and results from fundamental theoretical concepts, this book covers a broad range of two-dimensional structures--from overlayers to freestanding films. All those with an active interest in surface science and statistical physics will find this book to be an essential reference work. - Presents a coherent overview of experimental methods and theoretical background of two-dimensional crystal physics - Provides a tutorial overview of continuous melting of two-dimensional crystals, roughening transitions, wetting phenomena, and commensurate-incommensurate transitions

This thesis focuses on the study of the optical response of new atomically thin two-dimensional crystals, principally the family of transition metal dichalcogenides like MoS2. One central theme of the thesis is the precise treatment of the linear and second-order nonlinear optical susceptibilities of atomically thin transition metal dichalcogenides. In addition to their significant scientific interest as fundamental material responses, these studies provide essential knowledge and convenient characterization tools for the application of these 2D materials in opto-electronic devices. Another important theme of the thesis is the valley physics of atomically thin transition metal dichalcogenides. It is shown that the degeneracy in the valley degree of freedom can be lifted and a valley polarization can be created using a magnetic field, which breaks time reversal symmetry in these materials. These findings enhance our basic understanding of the valley electronic states and open up new opportunities for valleytronic applications using two-dimensional materials.

The success in creating atomically thin and mechanically robust two-dimensional (2D) crystals, starting with graphene, has unveiled new possibilities for next generation of ultrafast and ubiquitous electronics. One critical distinction between 2D crystals and 3D crystals is that 2D crystals are all-surface materials. Therefore, it is essential to understand how 2D materials interact with their environments and how this interaction impacts their electronic properties. From a practical perspective, it also provides us with a unique tool to tailor the electronic properties of 2D materials through surface functionalization. In the first half of this thesis, a suite of X-ray techniques is used to investigate how the surface functionalizing dopants will impact the electronic and chemical states of graphene. Based on this study, we develop an effective and non-invasive doping method for graphene through plasma-based chlorination. In order to make system-level 2D electronics successful, a flexible and ubiquitous energy harvesting solution is indispensable. Therefore, the second part of this thesis is dedicated to the development of a MoS2 2H-1T phase heterojunction-based GHz flexible rectifier as an enabling component for wireless energy harvester. It is the first flexible rectifier operating up to the X-band and it covers most of the unlicensed industrial, scientific and medical (ISM) radio band, including the Wi-Fi channels. By integrating this rectifier with an antenna, the MoS2-enabled rectenna successfully demonstrates direct energy harvesting of electromagnetic (EM) radiation in the Wi-Fi band and lights up a commercial light-emitting diode (LED) with zero external bias (battery-free). Moreover, our MoS2 rectifier also realizes successful frequency conversion as a mixer beyond 10 GHz on flexible substrates. This work provides a universal energy harvesting building block that can be integrated with various wearable electronic systems and paves the way towards using the existing Wi-Fi infrastructure as an energy hotspot for wireless charging.

Defects in Two-Dimensional Materials addresses the fundamental physics and chemistry of defects in 2D materials and their effects on physical, electrical and optical properties. The book explores 2D materials such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMD). This knowledge will enable scientists and engineers to tune 2D materials properties to meet specific application requirements. The book reviews the techniques to characterize 2D material defects and compares the defects present in the various 2D materials (e.g. graphene, h-BN, TMDs, phosphorene, silicene, etc.). As two-dimensional materials research and development is a fast-growing field that could lead to many industrial applications, the primary objective of this book is to review, discuss and present opportunities in controlling defects in these materials to improve device performance in general or use the defects in a controlled way for novel applications. Presents the theory, physics and chemistry of 2D materials Catalogues defects of 2D materials and their impacts on materials properties and performance Reviews methods to characterize, control and engineer defects in 2D materials

A large number of two-dimensional atomic crystals have emerged in recent years. The interatomic potential is a fundamental ingredient for the simulation of these atomic crystals. This book provides the parameters of the Stillinger-Weber potential for 156 two-dimensional atomic crystals, which will help readers to efficiently start up their simulations.

This book would be exciting to people that their interests broadly encompass condensed matter physics as a whole but lie in particular in the area of graphene-like 2D materials and in the area of superconductivity. The discovery of graphene opens up the possibility of new and exciting physics in a new class of materials. It was exhibited that single layer graphene can carry significant proximity supercurrents. Fabrication of graphene Josephson junctions enabled me to study the rare intersection of relativity and superconductivity. This initial work was extended to investigate 2D superconducting crystals of NbSe2. Our developed new mechanical exfoliation protocol enabled fabrication and measurement of superconductivity in several 4-point NbSe2 FETs devices. Results obtained on both graphene/NbSe2-FETs were encouraging and naturally suggest a number of extensions to this work. I would be excited to try and explore the combination of graphene and other 2d crystals by fabricating and characterizing such innovative prototype hybrid structures of these graphene-like 2D materials. I do believe that this research could play an important role in exploring new physics and device applications

This conference on liquid crystals of one- and two-dimensional order and their applications is the third in a series of European conferences devoted mainly to smectic liquid crystals. Its purpose was to bring together people working on the frontiers of the field of liquid crystals. Ordinary nematic liquid crystals were left out in order to limit the size of the meeting. The number of registered participants still reached 148. The conference shed new light on the classification of smectic mesophases, especially through the interaction of the Halle (GDR) and Hull (England) groups. It saw lively discussions on the famous blue phase of cholesterics. There were illuminating presentations on lyotropic nematic liquid crystals, on reentrant nematics, mesomorphic polymer phases, and related subjects. Much room was given to bilayers, monolayers, and interfaces, mostly to further the use of the concepts and methods of liquid crystal physics in exploring bio membranes. Other topics were device applications of smectic and cholesteric liquid crystals and nematic polymers, both of which hold promise of techno logical breakthroughs, apart from their scientific interest.

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Learn about the most recent advances in 2D materials with this comprehensive and accessible text. Providing all the necessary materials science and physics background, leading experts discuss the fundamental properties of a wide range of 2D materials, and their potential applications in electronic, optoelectronic and photonic devices. Several important classes of materials are covered, from more established ones such as graphene, hexagonal boron nitride, and transition metal dichalcogenides, to new and emerging materials such as black phosphorus, silicene, and germanene. Readers will gain an in-depth understanding of the electronic structure and optical, thermal, mechanical, vibrational, spin and plasmonic properties of each material, as well as the different techniques that can be used for their synthesis. Presenting a unified perspective on 2D materials, this is an excellent resource for graduate students, researchers and practitioners working in nanotechnology, nanoelectronics, nanophotonics, condensed matter physics, and chemistry.